1. Field of the Invention
The present invention relates broadly to the field of safety systems for use in controlling undesired flow of well fluids from hydrocarbon producing wells. Specifically, the present invention relates to an improved simplified construction of a primary rotatable ball-type surface controlled tubing retrievable subsurface safety valve which is procluded from ball rotational overtravel. The ball may be locked open in the event of a primary valve malfunction and a backup surface controlled through the flow line installed subsurface valve operably mounted therein as a redundant safety system.